If you liked the Fate/stay night anime, the Anime-Planet community thinks you'd like:
Minato Sahashi was living a normal life; he had just failed his college entrance exam for a second year in a row, and lived a quiet life in a single's apartment. That is, until the busty Musubi fell from the sky on top of him! She is a Sekirei, one of 108 that are destined to fight each other until only one remains; and he or she will ascend to heaven with his or her chosen one known as an Ashikabi. Minato soon finds himself in the embrace of Musubi, becoming her Ashibaki - but his life will only become more complicated. Musubi isn't the last to claim Minato as her Ashibaki, and what's worse, plenty of other Sekirei and opponents stand in his way!
in both series there are pairs of persons who have to fight each other in a series of fight set up by someone. You'll find more ecchi in sekirei, but the thing about the fights are more or less the same, also there's always kind of a person who is the master and the other who fights. they'll fight togueter against the other fighters to get to win and get to heaven in sekirei and get one wish on fate/stay night.
Both series have essentially the exact same concept behind them. There is a battle of superiority where all the others must be eliminated and the victors are awarded their wishes/heaven. In both, a master character is teamed up with a fighter character and together they must overcome the rest. Both series have an innocent yet very noble-minded male lead that is obsessed with protecting his female fighter(s) often ignoring the danger to his own life. Sekirei is more lighthearted, humorous, and ecchi, while Fate/stay night is more tragic and serious, but anyone who liked one will like the other.
are somewhat similar are both in a tournoment where they have they have to fight for their aster untill they are the only one left and all have powers
In a world where magic is a reality, the young Louise is at the bottom of her class. Dubbed "Zero" by her classmates at Tristein Academy (due to her zero success rate for magic), Louise (along with all first year students) was charged with summoning a familiar; and instead of a cute magical creature, the familiar arrived in the form of... Saito Hiraga, a normal Japanese boy who was abruptly teleported from his own world?! Can both Louise and Saito come to terms with their new and complicated "relationship" and (more importantly) help Saito find a way home?
Both Fate/stay night and ZnT deal with magicians and their relationships with their "familiars"; also, both magicians end up falling madly in love with their familiars, as well. If you liked one of these harem and fantasy-based series, you'll definitely like the other.
As both anime focus on magicians with their "summoned helper", the plots are rather different at some points. First they share the similarity of "doing what is right" which will lead to the inevitable dilemma's. In both series the main characters develop a love relationship with their "helpers".
The differences between the series are more at a sub-level: Zero no Tsukaima focusses more on humor and the main plot, so the action is more a side-show, where in Fate/stay Night the action is a bigger part of the show. Also, Zero no Tsukaima has some elements of ecchi in it. Where this usually is not a problem, in the second series of this anime there is more of it then in the first series and at a few points (not too many luckily) it can become annoying.
Overall, if you liked one, I do think you will like the other, even though both series have their differences.
Both of these shows revolve around a normal boy, magic, and familiars. Furthermore, the male leads in each have a large hero-complex, always attempting to do "the right thing," even if it risks their lives. Finally, both of these series have a theme relying on the evolution of the romance between the familiar/servant and the master. The difference, though, is ZnT is much more focused on the comedic aspect while FSN was more action based.
Seven years ago, Kakeru’s sister killed herself, leaving him alone. Now a teenager, Kakeru lives a quiet life with his friend Yuka and other classmates – but things change forever when he and Yuka are mysteriously transported to a frightening parallel world filled with monsters and a deep crimson sky. Though they manage to escape, Kakeru soon discovers that they aren’t alone; several other students at school also travel to the other dimension, and armed with powerful weapons they battle against its dark inhabitants. Why must they fight, and what is their purpose in the Red Night?
Well, both series show great resemblance, so if you like one, definitely try the other:
we have a fantasy in which a boy is pulled into a magical war fought by mostly teenage girls, besides his continuing life at school. The fights are mostly fought in an ambience of (relative) mid-darkness and also the weapons are comparable. He gets help from a girl coming from a family of magicians and who is also a participant in the war. And the evolution of love among the warriors is also a little part of the plot.
Both series are based on eroge (visual novels) and definetely show it. Plot-wise, they are similar in that a fantasy world involving war is suddenly thrust on the main characters, and they must choose how to survive in their new world.
Rokuro Okajima is a small-time salaryman who is carrying documents for his company, when the ship he's traveling on is attacked by pirates. Kidnapped, he discovers to his dismay that his employers' main concern is to ensure the documents don't get into the wrong hands, even if it means sending the carrier to the bottom of the sea. Now, with his former life ruined and his kidnappers seeming comparatively friendly, "Rock" decides to join their merry band of mercenaries, and sets out with a new career to the shadier corners of the South China Sea.
This recommendation may seem strange for some people as the story, art and such are all very different between Black Lagoon and FSN. This recommendation is for the person that likes strong female characters (more so in Black Lagoon) and some action mixed in. I just think if you liked one, you'd like the other.
Each of these series contain a strong female character that handles most of the violence that is present in each of them, and a main male character that is more or less pushed into an entirely new world that is marked with violence and death. Also, the main male attempts to act as somewhat of a moral conscience in each of the stories at some point.
It is the early 1920s, and New York City has a problem of evil proportions – demons. With devil worshipping on the rise, foul spirits and monsters have begun to surface, causing fear and panic in their wake. Combating this threat is the Magdalene Order – a group of religious officials charged with exorcising the evil that is spreading throughout the city. Rosette Christopher is a young nun who takes on missions alongside her contracted partner – a young demon named Chrono. Now it is up to this unlikely pair to wield God’s power – and plenty of holy bullets – to destroy the menace in front of them and confront the demons of their past.
In the beginning, both Chrono Crusade and Fate/stay night seem to be simple, but develop due to a massive yet unexpected turn of events and emotions. Also, they are both based around the Christian religion (though Fate/stay night is minimal in this regard and focuses only on the Holy Grail).
While Fate/Stay Night might be a bit more active and modern than Chrono Crusade, both of their plots run deeper than expected at first. When things gain a darker atmosphere, the characters and their actions start reminding you of each other more and more.